Run a tournament for some of the free engines I have with their default settings (hash table size was set to 512MB). They had 2 hrs for the first 40 moves and then 1 hr for the rest of the game (~6 hrs/game). The tournament had 6 rounds (126 games).

Here are the results:

Rank    Engine            Score    To           Ry          Gl           Fr           Sp          Na          St           S-B
1        TogaII 1.4-5c  25.0/36    ......     ===110    1010=1    ==111=    11=11=    =11==1    1====1    409.00
2        Rybka 2.2       24.5/36    ===001    ......     01====    =11===    ===1=1    111=1=    111111    376.00
3        Glaurung 2.2   23.5/36    0101=0    10====    ......     ==111=    ==1111    1=1===    11=011    376.50
4        Fruit 2.3.1      17.0/36    ==000=    =00===    ==000=    ......     010000    1=1111    111=11    252.25
5        Spike 1.2        15.0/36    00=00=    ===0=0    ==0000    101111    ......     =1=001    ==10==    245.50
6        Naum 2.0        11.0/36    =00==0    000=0=    0=0===    0=0000    =0=110    ......     =0=011    192.50
7        Strelka 2.0      10.0/36    0====0    000000    00=100    000=00    ==01==    =1=100    ......     171.75

Toga, Rybka and Glaurung got about the same number of points and were significantly better than the others.

(Hardware: 2.5GHz quad core Intel Xeon)

Have you tried Stockfish 1.4?  It's a derivative of Glaurung and is very, very strong.  (It always plays interesting, aggressive chess)

No, I haven't, but added it to the tournament. Thanks for the tip.

It'll take about two weeks to play all the games.

Just realized that I've forgot to post the result of the "extended" tournament. Stockfish turned out to be a Toga/Fruit killer.

   Engine                 Score     Ry       To       Gl          St        Sp        Fr         Na        St         S-B
1: Rybka 2.2        28.0/42 ······    ===001   01====  111=00  ===1=1  =11===  111=1=  111111  518.25
2: Toga II 1.4-5c  27.0/42 ===110  ······     1010=1  0==0==  11=11=  ==111=  =11==1  1====1  519.00
3: Glaurung 2.2    26.5/42 10====  0101=0  ······    1010==   ==1111  ==111=  1=1===  11=011  505.00
4: Stockfish 1.4    25.5/42 000=11  1==1==  0101== ······     1=100=  11111=  0==111   1=1100  503.50
5: Spike 1.2         18.0/42 ===0=0  00=00=  ==0000  0=011=   ······    101111  =1=001   ==10== 350.00
6: Fruit 2.3.1       17.5/42 =00===  ==000=  ==000=  00000=   010000  ······    1=1111  111=11  307.25
7: Naum 2.0         13.0/42 000=0=  =00==0  0=0===  1==000   =0=110  0=0000  ······     =0=011  272.75
8: Strelka 2.0       12.5/42 000000  0====0  00=100  0=0011   ==01==  000=00  =1=100   ······    259.25